Method and device for the production of rolls of web material without a winding core

ABSTRACT

A surface rewinding machine for the production of rolls of wound web material is described. The machine comprises: a winding cradle ( 1, 3, 5 ) for winding the web material and sequentially forming rolls (R) of wound web material; an insertion device ( 25 ) for inserting sequentially, into said winding cradle, winding spindles (M 1;  M) on which the rolls are formed; an insertion path for the spindles inside the winding cradle. A suction system ( 51 ) which follows the spindles along at least one portion of the insertion path so as to produce a vacuum inside the spindles is also envisaged.

TECHNICAL FIELD

The present invention relates to a rewinding machine for the productionof rolls of web material, for example rolls of so-called tissue paper,so as to obtain small rolls of toilet paper, all-purpose drying paperand the like.

The present invention also relates to a method for the production ofrolls without a central winding core.

BACKGROUND ART

In order to produce rolls or “logs” of web material, so-called rewindingmachines are commonly used, in which machines a predetermined length ofweb material is wound onto a tubular winding core normally made ofcardboard. These rolls or logs are then cut into a plurality ofsmaller-size rolls intended for sale. A tubular winding core sectionremains inside each small roll.

The winding machines of this type are divided into two categoriesdepending on the manner in which the winding movement is provided. In afirst type of rewinding machine, known as a central spindle rewindingmachine, a spindle supported on support elements between a pair of sidewalls receives a tubular winding core on which the roll or log is formedby means of rotation of the spindle which, for this purpose, isassociated with drive means. The winding movement is therefore providedcentrally by the spindle.

In a second type of rewinding machine, known as a surface rewindingmachine, the rotational movement of the tubular core on which the rollor log is formed is provided by peripheral members in the form ofrollers or rotating cylinders and/or belts with which the roll or log iskept in contact during formation. An example of a surface rewindingmachine is described in WO-A-9421545.

In both cases the end product contains a tubular core made of materialdifferent from that forming the roll.

In an attempt to obtain rolls provided with an axial hole, but without awinding core made of material different from that forming the roll,various systems have been studied. Italian Patent No. 1201390 describesa surface rewinding machine in which the cardboard tubular winding coreis replaced by a recyclable winding spindle. A system for extraction ofthe spindle from the finished roll and for recycling said spindletowards the zone for insertion into the rewinding machine is provideddownstream of the winding zone. A rewinding machine based on the same,concept is described in U.S. Pat. No. 5,421,536.

One of the difficulties of these machines and the associated windingmethods relates to the first winding phase when the leading edge of theweb material must be made to adhere to the spindle so as to startformation of the turns.

U.S. Pat. No. 3,869,095 describes a system in which a winding spindlereceives, mounted on it, a tubular core on which a roll of wound webmaterial is subsequently formed. The roll with its winding core is thenextracted from the spindle and the tubular core remains inside the endproduct. In this known machine both the spindle and the tubular core areprovided with holes so as to be able to suck the web material and windit around the winding core. The spindle is kept constantly connected tosuction means which follow the movement of the spindle during formationof the roll which is formed on a cradle defined by two parallel-axisrollers. Moreover, the spindle is supported by support slides whichtravel in lateral sliding guides and is gradually raised during winding.

EP-A-0 618 159 describes a spindle-type rewinding machine where therolls of web material are formed around a motor-driven spindle which issubsequently extracted from the roll. During extraction, a stabilizingfluid is introduced through holes formed in the spindle so as to ensurethe rigidity of the walls forming the axial hole of the roll. Thispublication also describes, in general terms, how the holes in thespindle may be used to suck the leading edge of web material. However,no system for applying the vacuum to the spindle is described.

Italian Patent Application No. 9652A/78, dated Dec. 1, 1978, describes asurface rewinding machine in which cardboard tubular cores which remaininside the finished roll are used for winding. A system for providingholes in the cardboard forming the tubular cores is also described. Asucking action is produced through these holes so as to cause theleading edge of the web material to adhere to the tubular core and allowwinding to be started. The vacuum inside the tubular core is produced bymeans of one or two suction ducts which are located in a fixed position,This device, therefore, is able to function only using particularly slowwinding methods in which the axis of the tubular core is not displacedor performs minimum movements until one or more winding turns have beencompleted. A system of blowing nozzles is also required in order tostart winding of the free leading edge around the tubular core.

OBJECTS AND SUMMARY OF THE INVENTION

One object of the present invention is to provide a method and a surfacewinding device which allow the production of rolls or logs without atubular core, in which the initial step for causing the free leadingedge of web material to adhere to the winding spindle is efficient, fastand reliable and is suitable for high production speeds.

A further object of the present invention is to provide a method and adevice of the abovementioned type, in which the step involvingextraction of the spindle from the finished roll or log is easy and isnot affected by the procedures used to start winding.

These and further objects and advantages, which will become clear topersons skilled in the art from a reading of the text below, areobtained by means of a surface rewinding machine of the type comprisinga winding cradle for sequentially forming rolls of web material, aninsertion device for inserting the winding spindles into the windingcradle and an insertion path for introducing the winding spindles intothe cradle. According to the invention, a rewinding machine of this typeis provided with a suction system cooperating with the spindles along atleast one portion of the insertion path so as to produce a vacuum insidethe spindles which have a wall which is permeable to air and typicallyprovided with a series of holes which could also have microscopicdimensions. The suction system follows the movement of the spindles overat least part of the insertion path. This enables high production speedsto be achieved.

With this arrangement, a vacuum is produced inside each spindle duringthe insertion movement of the spindle into the winding cradle. Duringinsertion, the leading edge of the web material comes into contact withthe external surface of the spindle and adheres to the latter owing tothe effect of the suction through the holes formed in the spindle wall.The holes may be distributed in various ways. One possibility consistsin a random distribution. Alternatively, the holes may be distributed inone or more lines which extend in a helical manner along the wholespindle. Or else the holes may be distributed in annular lines arrangedat suitable intervals along the axial extension. According to a furtheralternative, the holes are distributed along one or more alignedarrangements parallel to the spindle axis.

In a practical embodiment of the invention, the suction system maycomprise a nozzle, or preferably two nozzles, one for each end of thespindle, movable along an operating path along which the nozzle ornozzles are connected pneumatically to the inside of the spindle whilethe latter is inserted into the winding cradle, moving along theinsertion path.

The movement along the operating path and the form of the latter dependon the configuration of the rewinding machine. Generally, the presentinvention may be applied to any surface rewinding machine, independentlyof the configuration of the winding cradle. The latter may preferablyconsist, for example, of three winding rollers, as described inWO-A-9421545. However, the winding cradle may also be defined bydifferent winding members, for example systems of belts, combinations ofbelts or rollers or the like, as known to persons skilled in the art.

Although, in principle, it is possible to use a single suction nozzlepneumatically connected to the spindle, at one end of the latter, inorder to obtain a uniform vacuum and therefore a uniform suction effectalong the axial extension of the spindle, it is preferable to use twonozzles, one for each end of the spindle.

When the winding cradle comprises at least one first winding rolleraround which the web material to be wound is fed, it is possible toenvisage that the operating path of the nozzle or nozzles issubstantially circular, or more precisely in the form of an arc of acircle, with the center approximately on the axis of rotation of thefirst winding roller. According to the preferred embodiment of theinvention, it is envisaged that the first winding roller has, extendingaround it, a rolling surface (in a manner known per se, for example,from WO-A-9421545) which is substantially fixed with respect to the axisof rotation of the first winding roller. The operating path of thesuction nozzle or nozzles extends along the channel defined between thefirst winding roller and the rolling surface, while the spindle rolls onthe rolling surface, remaining in contact with the latter and with thesurface of the first winding roller or, more precisely, with the webmaterial conveyed around the latter.

The suction nozzle or nozzles, according to a possible embodiment of theinvention, are mounted on a unit rotating about the axis of the firstwinding roller. It is also envisaged providing a device which controlsthe movement of the unit about the axis of rotation of the roller insynchronism with the movement of the insertion device which sequentiallyinserts the spindles along the insertion path.

Essentially, in order to avoid problems of collision of the nozzles withother machine components, the movement of the nozzle is an alternatingoscillating movement instead of a continuous rotational movement. Duringforwards travel; the nozzles follow the movement of the spindle beinginserted. Once they have completed their function, the nozzles returninto the initial position with a movement in the opposite direction.

The oscillating movement of the unit supporting the nozzle or nozzlesabout the axis of the first winding roller may be obtained, for example,by means of a system comprising a motor and a pinion and crown-wheeltransmission system. However, according to a particularly advantageousembodiment of the invention, the rotating unit may support a small shaftwhich has an axis perpendicular to the axis of rotation of the firstwinding roller and on which a wheel is mounted in an idle manner. Saidwheel is made to roll over a surface not rotating with respect to theaxis of rotation of the first winding roller and over an annular surfaceof the first winding roller, perpendicular to its axis. In this way, aswill be clarified more fully below, the unit supporting the nozzle ornozzles moves at a speed equal to the speed of movement of theindividual spindles along the insertion path. This solution isparticularly advantageous because it is mechanically simple and can beeasily synchronized with the spindle movement, without the need forspecial measures.

Essentially, suction may be maintained until winding of the first turnof web material onto the spindle has been completed.

Further advantageous features of the rewinding machine according to theinvention are indicated in the accompanying dependent claims.

The winding method according to the invention envisages using suctionholes on the spindle and causing a leading portion of the web materialto adhere to said spindle by means of suction through said holesobtained by producing a vacuum inside the spindle. Essentially, windingis of the surface type and the suction is maintained inside the spindlealong a section of the insertion path which it follows within thewinding means.

In one mode of implementation of the method according to the invention,the winding spindle is introduced into a winding cradle along aninsertion path. A vacuum is temporarily produced along this path, insidethe winding spindle. The spindle may perform a rolling movement alongthe insertion path. The vacuum inside the spindle may be obtained byarranging next to one end thereof (or preferably both ends) a suctionnozzle which follows the movement of the spindle over at least a portionof the insertion path.

Further advantageous features and modes of implementation of the methodaccording to the invention are described in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be understood more clearly from a reading of thedetailed description which follows and with reference to theaccompanying drawings which show a practical embodiment of theinvention. More particularly, in the drawings:

FIG. 1 shows a cross-section along the line 1—1 according to FIG. 4, inwhich the suction device and the winding cradle can be seen;

FIGS. 2 and 3 show cross-sections similar to that of FIG. 1 during twosuccessive phases of the winding cycle;

FIG. 4 shows a cross-section along the line IV—IV according to FIG. 1;

FIG. 5 shows a schematic side view of the rewinding machine with thespindle extraction means;

FIG. 6 shows a view, similar to that of FIG. 1, of a second embodiment;and

FIG. 7 shows a view along the line VII—VII according to FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The invention is illustrated below with reference to application to asurface rewinding machine of the type described in WO-A-9421545. Furtherdetails regarding the machine and the winding method may be found insaid international publication. Those features necessary forunderstanding the present invention will be described below.

The rewinding machine comprises a winding cradle formed by three windingrollers indicated by 1, 3 and 5. The third winding roller 5 is mountedon an oscillating arm 7 which allows its movement in the direction ofthe arrow f5 so as to allow an increase in the diameter of the roll orlog L being formed. As is known per se, the first and the second windingroller 1, 3 form a nip 9 through which the winding spindle passes in themanner described below.

The nip 9 has, arranged upstream of it, a curved rolling surface 11defined by a comb-like structure through which a mechanism forinterrupting or cutting the web material, denoted by 13, passes. Thecurved rolling surface 11, which has a substantially cylindricalextension with an axis more or less coinciding with the axis of rotationA—A of the first winding roller 1, defines a channel 15 along which thepath for insertion of the winding spindles extends.

17 denotes generally an insertion device which has the function ofinserting the winding spindles M along the path for insertion into thewinding cradle 1, 3 and 5. In this embodiment, the insertion device hasa conveyor 19 comprising one or more flexible members in the form of achain or the like which are driven around a driving wheel 23 oppositewhich there is a pusher 25 rotating about an axis coinciding with theaxis of the driving wheel 23. Above the pusher 25 there is a resilientsheet 27 which has the function of keeping the spindle M in a positionready for insertion.

The mechanism described hitherto corresponds to that already describedin greater detail in WO-A-9421545, to the contents of which referencemay be made for further details. The difference consists in the factthat extractable and recyclable winding spindles M, which for exampleare made of plastic, replace the (usually cardboard) tubular coresconventionally used in this type of machine and intended to remaininside the end product.

As can be seen in particular in FIG. 4, a rotating unit 31 is supportedon the shaft 1A of the first winding roller 1 (mounted on the sides 20of the machine). Essentially two symmetrical units 31 are envisaged,being mounted on the two ends of the shaft 1A of the first windingroller 1. Only one of these units is illustrated in FIG. 4 and will bedescribed below.

The unit 31 comprises a sleeve 33 supported on the shaft 1A of thewinding roller 1 by means of bearings 35, 37. The sleeve 33 has anannular passage 39 defining a suction header pneumatically connected toradial holes 41 in the shaft 1A. Said holes are in turn connected to anaxial hole 43 connected to a suction pipe 45 situated outside the sidewall 20, by means of a rotating joint 46. The annular passage 39 definesa suction volume delimited by seals 47 in frictional contact with thecylindrical surface of the shaft 1A. The annular passage 39 ispneumatically connected to a duct 49 terminating in a suction nozzle 51.

A suction path is thus defined through the nozzle 51, the duct 49, theannular passage 39, the radial holes 41, the axial hole 43, the rotatingjoint 46 and the pipe 45.

The sleeve 33 may be adjusted in an axial direction on the shaft 1A bymeans of tightening grub-screws 53 which lock a ring 55 (on which thebearing 35 is fixed) opposite an annular groove 57 on the shaft 1A. Theannular groove 57 has dimensions in the axial direction such as to allowadjustment in the position of the sleeve 33. The adjustment is necessaryfor the purposes which will be described below.

The sleeve 33 has a tooth 32 (see FIG. 1) which cooperates with a fixedbut adjustable contact shoulder 34 mounted on the side wall of themachine. A resilient element 36, consisting of a helical extensionspring attached at 36A to the fixed structure and at 36B to the sleeve33, biases the sleeve 33 and therefore the entire unit 31 so as toassume the position shown in FIG. 1, where the tooth 32 rests againstthe fixed contact shoulder 34.

The sleeve 33 is integral with a shaft 59 on which a wheel 61 is idlymounted. The position of the shaft 59 and the diameter of the wheel 61are such that the latter makes contact with an annular surface 1B of theroller 1, perpendicular to the axis of the latter. In a positiondiametrically opposite to the annular surface 1B, with respect to thewheel 61, there is a plate 63 defining a surface 65 not rotating withrespect to the axis A—A of the winding roller 1. The plate 63 issupported by sliding bushes 67 sliding on guides 69 mounted on the sidewall 20 of the machine. The plate 63 may be displaced in accordance withthe arrow f63 in a direction parallel to the axis A—A of the windingroller 1 so as to be moved towards or away from the wheel 61. Thetranslatory movement in the direction of the arrow f63 is provided by acylinder/piston actuator 71 mounted on the side wall 20. In FIG. 4 theplate 63 is shown in solid lines in its position closest to the windingroller 1, where it makes contact with the wheel 61, while a position ofthe plate 63 where it does not touch the wheel 61 is shown in brokenlines.

When the wheel 61 is in contact with the annular surface 1B and thesurface 65 of the plate 63, it rolls on these two surfaces moving over acircumference having a center lying on the axis A—A of the windingroller 1. The axis C—C of the wheel 61 during this movement has anangular speed about the axis A—A equal to half the angular speed of thewinding roller 1. The advancing movement of the wheel 61 along thecircular path causes a corresponding rotation of the entire unit 31about the axis A—A of the winding roller 1. During this movement, thehelical spring 36 is tensioned.

When, on the other hand, the plate 63 is retracted and does not touchthe wheel 61, the latter rotates about its axis, but does not advance,and the unit 31 remains in the position shown in FIG. 1 owing to theaction of the spring 36.

The operation of the machine described hitherto is as follows. In thecondition shown in FIG. 1, the rewinding machine has nearly completedwinding of a roll or log L inside the winding cradle. The finished loghas already been partially moved away from the first winding roller 1and is in contact with the winding rollers 3 and 5. A new windingspindle M1 has been brought by the insertion device 17 into an insertionposition where it is retained by the resilient sheet 27. The unit 31 islocated in an angular position defined by the tooth 32 and the fixedcontact shoulder 34. The device 13 for cutting or interrupting the webmaterial N is located in the position ready to perform interruption ofthe web material. In a synchronized manner the pusher 25 pushes the newspindle M1 inside the channel 15 defining the insertion path, forcingsaid spindle between the curved surface 11 and the cylindrical surfaceof the first winding roller 1, the web material N remaining between thenew spindle M1 and the surface of the winding roller 1.

The spindle M1 starts to rotate along the curved surface 11 owing torotation of the winding roller 1. During this movement, the axis of thespindle M1 advances along a circular path with a speed equal to half theperipheral speed of the winding roller 1.

At the same time as the thrust exerted by the pusher 25 on the newspindle M1, the approach movement of the plate 63 towards the wheel 61is also caused by the cylinder/piston actuator 71, said plate havingremained until now in the retracted position shown in dot-dash lines inFIG. 4. Consequently, as the new spindle M1 starts to advance along theinsertion path defined by the channel 15, the nozzles 51 mounted on thetwo units 31 at the ends of the first winding roller 1 start to followthe same path followed by the spindle M1. As stated above, the speed ofmovement of the axis of the spindle M1 along the insertion path is equalto the speed of movement of the nozzle 51. Consequently, each nozzle 51remains facing the respective end of the spindle M1, as can be seen inFIG. 4.

There may be slight contact or also a very small distance between thefront surface of the nozzle 51 and the side of the spindle M1 so thatthe suction through the duct 49 creates a vacuum inside the spindle M1.This vacuum causes a sucking action through the holes MF formed in thecylindrical casing of the spindle M1. This sucking action causes the webmaterial N to adhere onto the external surface of said spindle.Consequently, when the cutting or interruption device 13 has causedcutting or tearing of the web material in a manner known per se (seeWO-A-9421545), the free edge which is produced by interruption of theweb material starts to be wound onto the spindle.

The sucking action is maintained over a portion of the section of thepath for insertion of the spindle between the positions shown in FIGS. 1and 2. The position shown in FIG. 2 corresponds to the situation wherethe web material N has been interrupted, producing a trailing edge NTwhich will be wound up onto the log L to be unloaded, and a leading edgewhich is being wound onto the new spindle M1. The angular positionassumed by the suction nozzles 51 represents the end position beyondwhich suction inside the spindle M1 is no longer required since at leastone turn of web material has already been formed around it. Therefore,the cylinder/piston actuator 71 may cause retraction of the plate 63which consequently no longer makes contact with the wheel 61. The latteris thus no longer forced to roll between the surface 65 and the surface1B of the winding roller 1, with the result that the spring 36 recallsthe unit 31 into the original position, bringing it into the conditionshown in FIG. 3.

A new spindle M2 is then positioned for the next winding cycle. In FIG.3 the spindle M1 is located at the exit of the nip 9 and is about tocome into contact with the third winding roller 5 which is lowered afterallowing expulsion of the previous log L.

In order to dampen the impact between the tooth 32 and the contactshoulder 34 during the return movement into the position shown in FIG.3, the tooth 32 may be lined with elastomer material.

Since the wheel 61 is subject to wear, in order to prevent it from nolonger making contact with the annular surface 1B, the possibility ofaxially adjusting the position of the sleeve 33 is envisaged (describedabove). Alternatively, it is envisaged that the shaft 59 supporting thewheel 61 may be mounted on the unit 31 in an oscillating manner and thatany wear of the wheel may be offset by greater oscillation of the shaft59 towards the surface 1B under the thrust of the plate 63.

The spindles M may be made as one piece and optionally divided in thecenter by a diaphragm. Alternatively, each spindle may be made as twoportions, each of which having a length equal to half the completespindle.

The unit 31 may be moved about the axis A—A of the winding roller 1 alsousing a different mechanism. For example, the sleeve 33 may be providedwith a crown wheel meshing with a pinion keyed onto an output shaft of amotor mounted on the side wall 20. The motor may rotate in bothdirections so as to cause an oscillating movement about the axis A—A ormay rotate always in the same direction so as to provide the unit 31with a continuous rotary movement. However, this second solutioninvolves design difficulties owing to the risk of the nozzles 51colliding, during a complete rotation, with other mechanical components.

The completed log or roll L is unloaded from the winding cradle 1, 3 and5 towards a station denoted generally by 80 in FIG. 5, where the windingspindle on which it has been formed is extracted so as to be recycledsubsequently towards the insertion device 17. The system for extractingthe spindle from the roll or log has, shown in schematic form, a jaw 82,opening and closing of which is performed by a cylinder/piston actuator84. The jaw 82 is mounted on a sliding block 86 sliding on guides 88.

Where the winding spindle consists of one piece, a single jaw 82 isprovided for gripping the end of the winding spindle projecting from thelog L. The projecting end has an annular relief MR (visible in FIG. 4)for allowing engagement with the jaw 82. If the spindle is made as twohalves, each of them has an annual relief projecting from the log L, anda pair of jaws 82 will be provided on the two sides of the machine inorder to extract the two portions of the spindle from the two ends ofthe log.

Basically the mechanism for extracting the spindle from the log L may beprovided as described in Italian Patent No. 1201390. FIG. 5 also showsschematically a recycling path 90 which conveys the spindles extractedfrom the completed logs towards a zone for removal by the insertiondevice 17. In this way, the logs produced by the machine will have anaxial hole without a central winding core.

FIGS. 6 and 7 show two partial cross-sectional views, similar to FIGS. 1and 4, of a different embodiment. The same or corresponding parts areindicated by the same numbers. In this embodiment, the suction nozzlebasically consists of a fixed suction duct 101 which has a mouth 101Ashaped along a circumferential arc extending over slightly less than90°, as can be seen in particular in FIG. 6. The mouth 101A follows thespindle insertion path.

The mouth 101A is closed by a wall 103 in the form of a circle segmenthaving a length about twice the length of the mouth 101A. The wall 103is movable angularly about the axis A—A of the winding roller 1. Themovement is provided (in the example shown in the drawing) by a motor105 which causes rotation of a pinion 107 meshing with a crown gearsegment 109 integral with the wall 103. Alternatively, it is possible toenvisage a moving system similar to that described in the precedingexample of embodiment for moving the suction nozzle 51.

A circular opening 111 is provided in an intermediate position of thewall 103. A seal 113 is arranged between wall 103 and the mouth 101A ofthe fixed suction duct 101 (FIG. 7).

When the opening 111 is located outside of the mouth 101A of the suctionduct 101 (as in the condition shown in FIG. 6), said mouth is closed bythe wall 103. When a new spindle M must be inserted into the insertionpath, the opening 111 is aligned with it, starting to move—as a resultof rotation of the wall 103 in the direction of the arrow f103 about theaxis A—A of the winding roller 1—so as to follow the movement of thespindle M. A vacuum is therefore produced inside the latter owing to theconnection, via the opening 111, to the fixed suction duct 101. Whenwinding of the first turn of web material around the spindle has beencompleted, suction may be interrupted and therefore the wall 103 withthe opening 111 returns into the initial position.

Essentially, the fixed suction duct 101 and the movable opening 111 forma suction nozzle which follows the spindle along the insertion path.

In this case also it is possible to envisage two symmetricalarrangements on the two sides of the machine so as to produce a balancedvacuum inside the spindle M.

It is understood that the drawing shows only one practical embodiment ofthe invention, the forms and arrangements of which may vary, without,however, departing from the underlying idea of the invention. Thepresence of any reference numbers in the claims which follow merely hasthe aim of facilitating interpretation thereof with reference to thepreceding description and the accompanying drawings, but does not limitthe protective scope thereof.

What is claimed is:
 1. A surface rewinding machine for the production ofrolls of wound web material, comprising a winding cradle for winding webmaterial and sequentially forming rolls of wound web material; aninsertion device for sequentially inserting, into said winding cradle,winding spindles having a wall permeable to air on which said rolls areformed; an insertion path for introducing said spindles into saidwinding cradle; and a movable suction system which is controlled such asto follow said spindles along at least one portion of said insertionpath so as to produce a vacuum inside said spindles.
 2. Machine asclaimed in claim 1, wherein said movable suction system is controlledsuch as to return to an initial position after insertion of a spindle,while a roll is still being formed on said spindle.
 3. Machine asclaimed in claim 1 or 2, wherein said suction system comprises at leastone suction nozzle movable along said insertion path along which said atleast one suction nozzle is pneumatically connected to the inside of thespindle which is inserted into said winding cradle.
 4. Machine asclaimed in claim 3, wherein two of said at least one suction nozzle arealong said insertion path pneumatically connected to two opposite endsof said spindle.
 5. Machine as claimed in claim 3, wherein saidinsertion path extends along a circumferential arc.
 6. Machine asclaimed in claim 5, wherein said winding cradle comprises at least onefirst winding roller which rotates about its axis and around which saidweb material is fed and wherein said insertion path has a center on theaxis of said first winding roller.
 7. Machine as claimed in claim 6,further comprising a rolling surface defining, together with said firstwinding roller, said insertion path for said spindles.
 8. Machine asclaimed in claim 6, wherein said winding cradle comprises a secondwinding roller defining, together with said first winding roller, a nipthrough which said spindles pass during winding.
 9. Machine as claimedin claim 6, wherein said at least one suction nozzle is mounted on arotating unit rotating about the axis of said first winding roller, andfurther comprising a movement device for controlling movement of saidrotating unit about said axis in synchronism with movement of saidinsertion device.
 10. Machine as claimed in claim 9, wherein saidmovement device causes a first rotary movement of said at least onesuction nozzle in the direction of feeding of the spindles along saidinsertion path so as to follow each of said spindles from an insertionposition to an intermediate position along said insertion path, followedby a movement in an opposite direction so as to bring back said at leastone suction nozzle from the intermediate position into the insertionposition.
 11. Machine as claimed in claim 9, wherein said movementdevice comprises a motor and a gear wheel transmission.
 12. Machine asclaimed in claim 9, wherein said movement device comprises a wheelmounted idle on a shaft perpendicular to the axis of rotation of saidfirst winding roller and supported by said rotating unit, and meanswhich oblige said wheel to roll on a surface not rotating with respectto the axis of rotation of said first winding roller and on an annularsurface of said first winding roller, perpendicular to its axis ofrotation.
 13. Machine as claimed in claim 12, wherein said means whichoblige said wheel to perform a rolling movement comprises a pressingelement movable in a direction parallel to the axis of rotation of saidfirst winding roller.
 14. Machine as claimed in claim 13, wherein saidpressing element defines said non-rotating surface.
 15. Machine asclaimed in claim 14, wherein said pressing element extends over aportion of a circumferential extension of said first winding roller. 16.Machine as claimed in claim 12, wherein said rotating unit is associatedwith resilient recall members.
 17. Machine as claimed in claim 3,wherein said at least one suction nozzle is movable along said insertionpath with an alternating movement between an initial position and an endposition.
 18. Machine as claimed in claim 3, wherein said at least onesuction nozzle is formed by a fixed suction duct and by a movableobturator arranged between the fixed suction duct and the spindles, theobturator following said spindles along said at least one portion of theinsertion path.
 19. Machine as claimed in claim 18, wherein said fixedsuction duct has a curved shape.
 20. Machine as claimed in claim 18,wherein said obturator consists of a movable wall adjacent to said fixedsuction duct and has an opening with dimensions smaller that said fixedsuction duct.
 21. Machine as claimed in claim 1, further comprisingdownstream of said winding cradle, an extractor for extracting thewinding spindles from each roll formed in said winding cradle; and arecycling path for conveying said spindles back towards said insertiondevice.
 22. A method for producing rolls of wound web material, withouta winding core, comprising the steps of: winding with a surface windingaction a portion of web material of predetermined length around awinding spindle for forming a roll; and extracting said winding spindlefrom said roll, characterized by: providing suction holes on saidspindle; providing at least one suction means cooperating with saidspindle so as to produce a vacuum inside said spindle; maintaining saidvacuum in said spindle while said spindle is displaced along aninsertion path towards a winding cradle, moving said suction means alongsaid insertion path; and causing a leading portion of said web materialto adhere to said spindle by means of said vacuum inside said spindle.23. Method according to claim 22, further including the step ofreturning said suction means into an initial position after adhesion ofsaid web material to said spindle while continuing winding of said webmaterial around said spindle.
 24. Method as claimed in claim 22 or 23,further comprising causing said spindle to roll along said path. 25.Method as claimed in claim 22 or 23 further comprising producing saidvacuum in said spindle by axially arranging a suction nozzle next to atleast one end of said spindle.
 26. Method as claimed in claim 25,further comprising arranging a suction nozzle next to each end of saidspindle.
 27. Method as claimed in claim 22, further comprising causingsaid at least one suction means to advance along said path in thedirection of insertion of said spindle.
 28. Method as claimed in claim27, further comprising moving said at least one suction means along saidpath with an alternating movement.
 29. Method as claimed in claim 22,wherein said insertion path extends substantially in the manner of anarc of a circle.
 30. Method as claimed in claim 29, wherein saidinsertion path has a center lying on the axis of a first winding roller,around which said web material is conveyed.
 31. Method as claimed inclaim 30, wherein said spindle is made to roll along said insertion pathbetween said first winding roller and an approximately cylindricalrolling surface extending around said first winding roller.
 32. Methodas claimed in claim 22, wherein the vacuum inside said spindle ismaintained until a turn of web material has been wound around thelatter.